This invention relates to a multiple-tube dispenser. Devices of this type are used for simultaneously dispensing two or more components which react to form ready-to-use composition, such as dental cements or adhesive substances, which require the components to be discharged always at the same predetermined volume ratio.
U.S. Pat. No. 2,826,339 discloses a dispenser in which a body includes a plurality of nested cylindrical chambers all of which except the innermost are of annular cross-section. Pistons provided in the chambers are advanced by a commom plunger arrangement which is actuated by a threaded spindle engaging a closure member provided at the rear end of the innermost cylindrical chamber.
Due to the annular shape of the chambers, the pistons and the plunger arrangement, the known multiple-tube dispenser is very difficult to manufacture at reasonable tolerances, and the substantial friction of the annular pistons render the device hard to handle. An additional serious disadvantage resides in the face that, when the chambers have been emptied, a time-consuming procedure is required to remove the plunger arrangement with the threaded spindle by rotating the spindle all the way back in the reverse direction. Such a removal is necessary if it is required to reuse the threaded spindle, possibly also the plunger arrangement, whereas the tube body will regularly form a disposable one-way item.
Double-tube dispensers are known from German patent specification No. 1,411,642 and from German utility model specification No. 6,937,543, in which the plunger arrangement is moved into the tube body from the rear end thereof by a simple translatory movement. In this case, it would be possible to withdraw the plunger arrangement by a correspondingly simple straight movement if the plunger arrangement were to be re-used--which has not been considered. However, these known devices have no threaded spindle, so that it is required manually to apply a pressure on the plunger arrangement for dispensing the components. Depending on the viscosity of the components, this may again result in a difficult handling. Moreover, it is practically impossible with these devices to discharge exactly metered amounts of the components.
U.S. Pat. Nos. 2,745,575 and 3,353,718 disclose dispensing devices operating with a threaded spindle which may be released from its engagement with an internal thread by actuating a slider, whereupon the spindle may be removed from the tube. It is further known from French Pat. No. 585,633 to form the counter-thread for a threaded spindle by two portions of a tube cover, so that the spindle may be removed upon opening the cover and separating the two portions thereof. These three last-mentioned devices, however, are single-tube dispensers and therefore cannot be compared to multiple-tube devices in which the plunger arrangement required for simultaneously advancing all pistons necessarily complicates the overall structure.
It is an object of the invention to provide a multiple-tube dispenser which allows simple and quick assembly and disassembly of its various parts, so that some of them may readily be re-used. A further object of the invention is to provide a dispensing device which permits a simultaneous discharging of two or more components at a predetermined ratio in predetermined amounts. As a further object of the invention, a multiple-tupe dispenser is to be achieved which is inexpensive to manufacture and easy to handle.